1) Head - The main horizontal member forming the top of the door frame.

2) Meeting Rail - The horizontal sections of a pair of sashes that meet when the sashes are closed.

3) Tempered Glass

4) Insulating Glass Unit (IG) - An enclosed, dehydrated and hermetically sealed air space between the panes of glass.

5) Sash - The operable glass panel.

6) Sill - The main horizontal member forming the bottom of the frame of a window or door giving the unit better water drainage.

7) Glazing - Glass in a window or patio door; the act or process of fitting with glass.